IMPROVEMENT IN SUBGRADE SOIL BY ENVIROTAC II.

The  subgrade  conditions which  are poor  can  result in inadequate pavement support which may  reduce pavement life. Soils may be improved by adding polymers, chemical or cementitious additives. Polymers are used worldwide for stabilization of soil. Polymer used are polyvinyl acetate, polyacrylamides and polybutadienes.   These additives can be used with a variety of soils to help improve their native engineering properties. The effectiveness of these additives depends on the soil treated and the amount of additive used. Envirotac II consists of environmentally safe, high performance Vinylacatae co-polymer which works on the principles of nano-technnology .It was found that with the addition of stabilizers i.e. polymers and cement, the C.B.R. increased upto a certain limit but after that the C.B.R. decreased even on the further addition of stabilizers. The Envirotac II was added percentages ( 1%, 2%, 3%, 4% and 5%) to the subgade soil with clay and silt content 84% and sand content 16%, MDD(1910 Kg/m³ ), OMC(13%) and CBR% (4.09). At optimum dose of 4% MDD(1994 Kg/m³), OMC( 10.1%) and   CBR % (21.90) were achieved. Thus there was a sharp increase in CBR  upto 435 % at optimum dose of 4%. The same soil was treated with different %ages  of cement (2%, 4%, 8%, 12% and 15%). For the dose of 15% cement MDD (2005 Kg/m³ ), OMC(11.50)  and  CBR(7.90) were achieved. There was a gradualincreaseinCBRupto 93.15 % at 15% addition of cement. Thus Envirotac II can stabilize the subgrade soil with much more with less dose as compared to cementitious additives.